a) Field of the invention
The present invention relates to a joint for manholes and drains. More specifically, the invention concerns a sealing device for tube sections and concrete rings connected end to end by means of a joint and adapted to prevent aggregates and other noxious and undesirable materials to be introduced into the joints when a space is produced in the latter following climate modifications or other disturbances, such as during thawing and unthawing periods.
b) Description of Prior Art
It is known that the assembling of manhole tubes and rings, and drains imply the end to end connection of a plurality of sections of which the number varies depending on the depth which is intended to be reached. Generally, the different sections of tubes and rings are usually connected by means of lap joint connections. Now, in theory, even during a period of thawing and unthawing, it is essential that the different sections of tubes and rings always come back to their initial position after any kind of movement of the ground, if it is intended that the frame and the grid which covers them always remain in the same position with respect to the surface of the ground. In practice, each movement of the ground nearly always produces a space in the joint between the sections of tubes and rings, thus giving free access to the aggregates and other undesirable materials. In is obvious that following an accumulation of some importance in the joint, the frame and the grid will never return to their original position. In order to prevent the aggregates and other undesirable materials from being introduced into the joint, sheets of polyethyl or paper, with which the joint is covered, are often used. It is certain that the important stresses which are involved do not prevent these sheets from being torn thus rendering this precaution completely useless.
U.S. Pat. No. 4,076,283 describes an intricate system of expansion joint for drain pipes including a flexible band which is fixed on a pipe and is curved unto itself, to be fixed on the adjacent pipe.
U.S. Pat. No. 4,116,474 describes a joint system including a sealing ring having a plurality of characteristics, in which an insert device is introduced.
U.S. Pat. No. 4,325,572 describes a intricate arrangement having a double curve.
U.S. Pat. No. 4,443,282 describes a pipe coupling including a sealing ring having a plurality of characteristics, in which an insertion socket is introduced.
U.S. Pat. No. 4,325,572 describes a complex system utilizing a sealing cuff folded into an S configuration.
U.S. Pat. No. 4,443,282 describes a ring joint utilizing a sealing material within and under the ring.
Finally, U.S. Pat. No. 4,703,940 describes the use of a compression ring in combination with a sealing ring.
It will therefore be seen that attempts have been made to solve the problem discussed above. However, these attempts are all more complicated and expensive than the others without ensuring that the questions has been resolved..
It is therefore all object of the present invention to provide a solution to the joints between sections of tubes and rings of manholes and drains, which is easy, rapid and efficient.